Fuel nozzle for oil furnaces



Sept. 24, 1935. A. wETTsTElN FUEL NOZZLE FOR OIL FURNACES Filed Oct. 25, 1954 Patented Sept. 24, 1935 FUEL NozzLE FOR oIL FURNACES August Wettstein, Baden, Switzerland, assignor to Aktiengesellschaft Brown, Boveri & Cie., Baden, Switzerland, a joint-stock company Application October 23, 1934, Serial No. 749,595 In Germany November 4, 1933 8 Claims.

This invention relates to fuel burners or nozzles for oil furnaces, and particularly to fuel nozzles that may be adjusted over a wide range of load limits.

It has been the practice to employ a plurality of small nozzles or burners in the re chamber of a furnace which -is to be operated under varying loads as it has not been possible heretofore to regulate nozzles over a wide range of load, especially those nozzles which are designed to effect a mechanical atomizing of the fuel. When operating under small loads, a number of the nozzles are put out of operation but the switching in and out of new nozzles causes an abrupt variation of the fuel feed which results in poor combustion and fluctuation of the regulation. There is also the danger that the nozzles which are not in operation will be clogged by the coking of the fuel residue or will be lburned or damaged by the high temperature in the fuel chamber.

An object of the present invention is to provide a fuel nozzle or burner for liquid fuel that may be adjusted over a very wide range of load limits. An object is to provide a fuel nozzle or burner which includes a plurality of adjustable nozzles of different sizes that are arranged within each other, preferably concentrically, and which may be placed in operation successively in accordance with the fuel demand. -A further object is to provide a fuel nozzle or burner which includes a plurality of eoncentrically arranged and telescoped fuel nozzles, each nozzle including an atomizer head and a valve plunger for regulating the flow of fuel through the atomizer head, the atomizer head of each smaller nozzle forming the valve plunger of the next larger nozzle. A further object is to provide a fuel nozzle or burner including a plurality of concentrically arranged nozzles of different capacities and a single regulating member for progressively placing the several nozzles in operation, the movement of each larger nozzle into operating condition being automatically accompanied by a closing of the next smaller nozzle.

These and other objects and advantages of the invention will be apparent from the following specification when taken with the accompanying drawing in which:

Fig. 1 is a fragmentary transverse section through one embodiment of the invention, as taken on line I-I of Fig. 3;

Fig. 2 is a longitudinal section showing the parts in closed position;

Fig. 3 is a fragmentary transverse section of the same but showing'the smaller nozzle closed REISSUED and the larger nozzle in partly open position; and

Figs. 4, 5 and 6 are fragmentary longitudinal sections illustrating typical embodiments of the invention. 5

For simplicity and clearness of illustration, the several views of the drawing illustrate burners having two nozzles, but it is to be understood that the invention is not limited to this or any other number of nozzles.

In the drawing, the reference numeral I identifies the cylindrical shell of the multiple nozzle burner which is provided with a fuel outlet 2 that is inwardly flared from both faces of the end wall to forman atomizing orifice. The inner 15 flared face of the opening 2 constitutes a valve seat which is engaged by the correspondingly flared tip of the valve plunger 3 which, in ac cordance with this invention, is designed as a fuel nozzle. 'I'he member 3 is a hollow sleeve 20 within which the valve plunger 4 is slidably mounted, the lower face of the valve plunger 4 being flat to engage the end surface of the member 3 which is provided with a central atomizing orifice 5. The apertured end walls of the members I and 3 constitute nozzles for projecting a stream of atomized fuel into the combustion chamber but for convenience of description these elements will be defined in the following specication and claims as atomizer heads. As shown in Fig. 2, the outer surface of the orilce 2 has a somewhat greater slope than the outer surface of the orifice 5 to provide clearance for the rotating stream of atomized fuel which is discharged from orifice 5 when the burner is operated under relatively light loads.

The member 3 is slidably mounted in the sleeve 6 which is mounted in the shell I by its inner enlarged portion that is apertured to permit the passage of fuel from the hollow burner mounting 'I 40 into the annular space 8 at the outer end of the burner head I. The outer end of the sleeve 6 is provided with a number of tangential passages 9 which open into the annular space I0 between the conical end of the member 3 and the end wall 45 of the sleeve I, and similar tangential passages I I in the member 3 afford communication between the chamber Ill and the interior chamber of the member 3. The several passages' of each set are axially spaced to provide graduated control of the 50 fuel supply as the valve plunger of each atomizer head is progressively displaced.

The member 3 is normally retained in its outer position by the spring I2 and the initial displacement of the inner valve plunger I does not result 55 in a movement of the member 3, since the collar 4' on the valve plunger 4 has a limited range of sliding movement within the member 3. The plunger 4 is actuated by and may be integral with the control member I4 of the fuel regulator, not shown, which may be and preferably is of the automatic type.-

As shown in Fig. 2, the plunger 4 is seated on the end of the member 3 and interrupts all flow of fuel to the nozzle. For relatively light loads, the plunger 4 will be displaced to uncover one or more of the fuel passages II to regulate the flow of fuel through the orifice 5 of the inner atomizer head. It is well known' that the maximum amount of fuel which may be discharged through a. nozzle of this type is limited by relatively strict design requirements which have resultedin the present practice of employing a plurality of separate nozzles when the fuel demand exceeded the maximum output of a single small nozzle. In the present construction, the continued inward movement of valve plunger 3 after the last passage II has been cleared brings the collar 4' into engagement with the inturned fiange of the member -3 and results in an inward movement of the member 3. When this takes place, fuel is discharged directly from the chamber I0 through the orifice 2 of the outer atomizing head. At the same time, the member 3 is forced inwardly by the Afiuid pressure within the chamber I0, since that pressure now acts upon that portion of the conical end of member 3 which was previously seated upon the flared inner surface of the orifice 2 (see Fig. 3,). The passages 9 are so proportioned that the flow of fuel through the outer atomizer head atthe instant of the opening of its valve plunger is substantially equal to the maximum iiow of fuel through the inner atomizing head. For heavier loads, the fuel supply through the outer atomizing head is increased by the progressive movement of the member 3 to uncover additional passages 9.

It will be apparent that the same principles may be embodied in a burner which includes more than two atomizer heads but, in general, two atomizer heads will afford a sucient range of control. If the inner head is given such dimensions, for example, that it has a maximum output equal to one-fourth the maximum output of the outer head, and if the greatest amount of fuel that can be handled with efcient atomizing by each head is equal to about four times the smallest amount, the range of regulation of the double atomizing head is therefore one to sixteen. As both heads are constantly bathed in fuel which fiows around them on all sides, undesired heating and clogging are avoided.

For smooth operation, the change from one nozzle or atomizer head to another should be made as quickly as possible and the nozzle which comes into operation should deliver substantially the same quantity of fuelas the nozzle which goes out of operation. This second requirement may be satisfied by an appropriate design of the fuel passages 9, II, and the pressure of the fuel may be employed to effect a quick change over from one nozzle to another.

In the embodiment of the inventionA which is shown in Fig. 4, the outer shell I' is provided with an integral sleeve 6 within which the hollow plunger I5 is slidably mounted, the lower end of the sleeve having a set of tangential fuel passages 9 which open into the annular chamber I D that is formed by circumferentially grooving the plunger I5. A set of tangential fuel passages II extend through the'wall of the plunger I5 and, as in the previously described form of the invention, the shell I and plunger I5 have atomizing orifices 2, 5, respectively. The inner end of valve plunger I5 is provided with a piston I6 land cylinder I1 which is telescoped within the cylindrical exten- 5 sion I8 of a guide member I9. The guide member has lateral ports for passing fuel to the lower chamber 8 and a central bore'in which the control rod 20 is slidably mounted, the lower end of the rod serving as the valve plunger of the inner 10 atomizer head. TheA outer plunger member I5 is normally retained in outermost position by a spring I2 and by pressure of the fluid fuel which ls admitted to the interior of the telescoped cylinders through the port 2| and ring chamber 22 in guide A15 member I9, and the longitudinal grooves 23 of the control rod 20. The lower ends of grooves 23 terminate at such a level as to interrupt the communication of the fuel supply with the ring chamber 22 when the rod 20 is displaced to estab- 20 lish maximum flow through the inner atomizing head and, simultaneously, the pressure within the telescoped cylinders is relieved as the reduced diameter section 24 of the rod 20 moves into alinement with ring chamber 2|, the pressure cham- 25 ber exhausting through the bore 24' of rod 20 to a space of lower pressure than the incoming fuel, for example to the main fuel tank. As the fuel is supplied to the burner under high pressure, the

excess pressure on the outer face of piston I6 3'0`f forces the member I5 inwardly rapidly, thus cutting off flow of the inner atomizer head and opening one or more of the fuel passages 9 to deliver approximately the same quantity of fuel through the outer atomizer head as was previously dis- 35' charged through the inner atomizer head.

In place of the telescoped cylinders I1, I8, the pressure chamber may be formed by a sylphon bellows I1 which extends from the inner face of pistou I 6, Fig. 5, to the guide member I9. 40 The other parts of this embodiment of the invention may be substantially identical with corre- .sponding parts of the Fig. 4 embodiment, and are therefore identified by like reference numerals but will not be described in detail. 45

The form of the invention shown in Fig. 6 provides a more convenient method of disposing of the excess fuel within the pressure chamber when the outer atomizer head is placed in operation.

The pressure chamber is constructed substantially 50 as in the Fig. 5 embodiment but the channels 23 in control rod 20' extend directly into the pressure chamber. The lower face of the guide member I9 is provided with an annular valve seat 25 for cooperation with the sleeve valve 26 that 55` is slidably mounted on the control rod 29'. The valve plunger end 21 of the rod 20' is of reduced diameter and the outer end of the sleeve valve 26 is inturned and normally held against the radial shoulder on rod 20 by the spring 28. The 60 valve sleeve 26 has an internal ring chamber 29 that opens into the counterbore 30 in the valve plunger 21, but this ring chamber is normally sealed against the pressure fluid by the engagement of the flanged end of the sleeve valvev with 65 the radial shoulder on rod 20'.

When the valve plunger 2-'I has fully opened the fuel passages to the inner atomizer head, a further movement of the control rod 20 brings the valve sleeve 26 into engagement with the 70 valve seat 25 and thus seals off the pressure chamber. Further movement of the control rod opens the ring chamber of the sleeve valve to the pressure chamber, thus placing the pressure chamber in communication with the fire chamber through 75 the bore 3l. The high pressure of the fuel in chamber 8 causes a quick collapse of the sylphon bellows, closing the inner nozzle or atomizer head and opening the fuel passages to the outer atomizer head.

It will be apparent that the invention is not limited to the particular constructions herein illustrated and described, as the exact number of nozzles included in the burner may be variedv to meet different requirements and the mechanism for shifting from one nozzle to another is subject to considerable variation.

I. claim:

1. A burner comprising a plurality of telescoped nozzles, each nozzle including an apertured sleeve terminating in an atomizer head and a Avalve plunger adjustable within the sleeve to control the delivery of fuel through the apertures thereof,

the sleeve and atomizer head ofA an inner nozzle constituting the valve plunger of an adjacent outer nozzle, the apertures in said sleeves comprising a plurality of tangential fuel passages axially spaced apart along said sleeves whereby said fuel passages may be progressively opened by axial displacement of said valve plungers.

2. A burner as claimed in claim 1, in combination with means operable upon a displacement into fully open position of the valve plunger of the inner nozzle to close 'the apertured sleeve of the inner nozzle upon that plunger, thereby placing the outer nozzle in operation.

3. A multiple nozzle burner comprising an outer nozzle including a sleeve terminating in an atomizer head, axially spaced fuel passages extending through said sleeve, a valve plunger slidable in said sleeve to control th'e f iow of fuel through said passages, said valve plunger being an apertured sleeve terminating in an inner atomizer head, a control member slidable in said valve plunger to control the flow of fuel through the inner atomizer head, means normally retaining said valve plunger in position to prevent fuel flow through the outer atomizer head, and means operable when said control member has fully opened the inner atomizer head to render said retaining means inoperative and to move said valve plunger to close said inner atomizer head, thereby opening said outer atomizer head.

4. A burner as claimed in claim 3, wherein said retaining means comprises means defining a pressure chamber for holding said valve plunger in position to prevent fuel ow to the outer atomizer head, inlet and outlet passage means for controlling the ow of a pressure fluid'though said passage mea l v 5. A m tiple nozzle burner comprising a hollow burner head and means for introducing iiuid` 5 fuel into said head, an atomizng orifice at the end of said burner head, a sleevewithin said head and provided with a plurality of tangential and axially spaced passages through the wall thereof, a plunger slidable within said sleeve to 10 control fuel flow through said passages, said plunger cooperating with said sleeve and orice to form an outer nozzle, said plunger being hollow and terminating in an atomizng orifice lconstituting an inner atomizer head telescoped within 15 said outer nozzle, tangential and axially spaced fuel passages in the wall of said plunger, a control member slidable within said plunger to control t said plunger moved thereby to admit fuel to the outer nozzle. Y

- 6. A burner as claimed in claim 5, wherein said means cooperating with the piston to define a pressure chamber is a cylinder xed to the piston and telescoped within a cylinder fixed to said burner head.

7. A burner as claimed in claim 5, wherein said means cooperating with the piston to define a pressure chamber isa sylphon bellows having one 4u end closed by said piston and its opposite end iixed to said burner head.

8. A burner as claimed in claim 5, wherein said means cooperating with saidl,piston to form a pressure chamber includes a guide member in which said control member is slidably mounted,v said inlet passage means comprises a longitudinal channel in said control member, and the means to close said inlet passage means comprises a valve seat on said guide member and a sleeve valve mounted on said control member.

AUGUST WETISTEIN. 

